This invention relates to polymers of 4-methyl-1-pentene (p-4MP-1) having a high degree of terminal 1,2-disubstituted olefinic unsaturation, methods of making such polymers, derivatives thereof, and compositions and end-uses employing the same.
Polymers, including homopolymers of a single monomer and copolymers synthesized from one or more monomers, containing a high degree of chain terminating 1,2-disubstituted olefinic unsaturation are known to be useful for post-polymerization reactions. Due to the greater reactivity of such ethylenic unsaturation compared to more sterically shielded vinylidene functionality, reactions such as grafting with other ethylenically unsaturated moieties or insertion polymerizations, where the vinyl-terminated polymers are copolymerized with insertion polymerizable monomers, are greatly facilitated. Moreover, certain finishing operations such as painting, laminating, or adhering objects and articles molded, extruded or otherwise formed from such polymers are also benefited. Because the polymers containing 1,2-disubstituted olefinic unsaturation are often used in further polymerization processes, as curing agents or as components of blends, they are often referred to as macromonomers, or simply macromers.
Many useful polymers containing terminal 1,2-disubstituted olefinic unsaturation have been developed in the art and are used in industrial processes in forming articles and blends, in forming further functionalized derivatives, and in the manufacture of branched polymers. Examples of prior art stereospecific propylene macromers are found in U.S. Pat. No. 6,117,962, and elsewhere. Due to the low crystalline melting points of such propylene based macromers, they are limited to use in applications having low service temperatures.
Homopolymers and copolymers of 4-methyl-1-pentene, especially stereospecific, and in particular, isotactic versions thereof, are known to generally possess higher crystalline melting point than corresponding polymers of propylene. Examples of such p-4MP1 compounds as well as blends and compositions incorporating the same are disclosed in U.S. Pat. Nos. 4,342,854; 4,659,792, 5,025,057, 5,182,330, 5,338,792, 5,689,484, 5,922,812, 6,458,890, and elsewhere. The polymers are prepared by the use of known addition polymerization catalysts such as Ziegler-Natta, metallocene and chromium based organometallic catalyst compositions. However, such catalysts, especially metallocenes, disadvantageously require the use of a chain termination agent, such as hydrogen, in order to obtain meaningful quantities of polymeric product.
Unlike polyethylenes, which can be made with high terminal olefinic unsaturation, similarly terminated p-4MP1 compositions, especially those having a high 4-methyl-1-pentene content or a high degree of stereospecificity, are rare or non-existent. While regular β-hydride elimination gives the desired terminal functionality in ethylene, β-alkyl group elimination, a less favored process, is necessary to provide similar functionality in polymers of higher α-olefins. Moreover, use of hydrogen or other chain transfer agent in a polymerization process gives saturated chain terminal groups, thereby completely eliminating formation of terminal 1,2-disubstituted olefinic unsaturation where a chain transfer agent is utilized. Because 4-methyl-1-pentene has not previously been found to be readily polymerizable by metallocene or other stereospecific polymerization catalysts in the absence of such chain terminating agents, formation of p-4MP1 products containing 1,2-disubstituted olefinic unsaturation has been previously unattainable.
In U.S. Pat. Nos. 6,713,557 and 6,750,345 certain pyridyl amine and substituted pyridyl amine complexes of transition metals, especially hafnium, are disclosed for use as olefin polymerization catalysts. Among the suitable olefins said to be usefully polymerized is 4-methyl-1-pentene (see, col. 77, lines 16 and 22, respectively), however, no p-4MP1 products were prepared.
Despite the advance in the art occasioned by the foregoing researchers, there remains a need to develop certain polymeric derivatives of 4-methyl-1-pentene having improved levels of terminal 1,2-disubstituted olefinic unsaturation functionality, to develop functionalized derivatives thereof, as well as to develop methods for forming and utilizing such polymers and functionalized derivatives.